Regulator



Dec. 8, 1925- 1,564,682

r J. L. KIMBALL REGULATOR Original Filed March 7, 1921 2 ShQGtS-ShGt 1FIG! - IYVVE'NTOR.

Dec 8, i925 REGULATOR FlGE.

Patented Dec. 1%25.

W mm. a.

JAliflEs LEWIS KIMBALL, 0i? SALEM, MASSACHUSETTS, ASSIGNOR TORUGGLES-KLING-E- ML'ANN MFG. (30., 035 SALEM, MASSACHUSETTS, ACORPORATIQN 01E MASSACHUSETTS.

REGULATQR.

Original application filed March 7, 1921, Serial No. 450,376. Dividedand this application filed October 23, 1923. Serial No. 670,344.

To all 'LU/LO/Ib it may concern.

Be it known that I, JAMES LEWIS KIM- BALL, a citizen of the UnitedStates, and a 'resident of Salem, in the county of Essex andCommonwealth of lilassachusetts, have invented a new and usefulImprovement in Regulators, of which the following is a specification.

The present invention relates to control systems, and more particularlyto regulators for regulating the. pressure of fluidpressure systems. Thepresent application is a division of a copending application, Serial No.450,376, filed March 7, 1921.

Pressure systems are commonly autopressure devices having diaphragmsthat are responsive to variations in the pressure of the system. Thediaphragm acts upon a scale beam that controls a valve for admittingfluid underpressure to one side or the other of a fluid-operated, damper-actuatll'lt! motor (see the definition of the term damper hereinaftergiven), thereby automutically regulating the pressure of the system soas to maintain it within predetermined limits. I

Regulators of the above-described character have a tendency to hunt.Briefly stated, hunting action is a fluctuation of the pressure due to asupply in excess of the demand. An air supply in excess of the boilerload, by producing an excessive blowing period and, therefore, acorresponding idling period, neither of which represents the true loadvalue, will cause hunting.

The motor and. therefore, the damper controlled thereby, are actuated toa position somewhat beyond that required by the value of the pressurethat caused the motor actuation. The pressure is thus caused to build upto a value too far to one side of the normal. The regulator thereuponproreeds to operate in the opposite direction, but does not becomechecked until the pressure attainsa value too far to the other side ofthe normal. To reduce this hunting effect, various compensatingimprovements have been introduced, among them a mecha nism for graduallycounteracting the force exerted by the diphragm upon the scale beam.Sudden and too rapid response of the valve is thereby prevented, and thetendency to hunt is reduced. Hunting has not, however, been completelyeliminated.

It is an. object of the present invention, therefore, to reduce to aminimum the above described hunting tendency.

To the accomplishment of this object, the counteracting force upon thediaphragm is exerted, not gradually or uniformly, but step by step,permitting free play for the regulator between steps, but suddenlychecking any further action at the limiting points of the steps.

.lVith the above and other objects in view,

v as will be clear to persons skilled in the art, matically regulatedthrough the agency of the invention consists of, the improved regulatora preferred embodiment of which is hereinafter described, illustratedin'the accompanying drawings, and defined in the appended claims.

lln the drawings, Fig. l is a diagrammatic elevation, partly in section,of a regulator constructed according to a preferred embodiment of thepresent invention; Fig. 2 is an enlarged section of the valves shown inFig. 1; and Figs. 3 and 4: are diagrammatic views, illustrative ofvarious devices that may be controlled by the regulator of the presentinvention.

As above stated, the present invention relates more particularly to thecontrol or regulation of fluid-pressure systems. The

invention is illustrated, in its preferred form, as applied to theregulation of a steam-pressure system (not shown) that operates asteam-pressure device in accord ance with the pressure obtaining in thesteam-pressure system. The steam-pressure device comprises a pressurechamber 1 that is connected to the steam-pressure system by a steampipe3. The pressurechamber 1 contains a diaphragm 2. The diaphragm 2 is thusmade responsive to the pressure in the system to operate, through apressure cap 4, a scale beam 5. The scale beam is intermediatelyfulcrumed at 6, Weights 7 at the other end of the scale beam exerting aforce upon the scale beam in opposition to the force exerted by thediaphragm 2.

The inevements of the scale beam 5 are cominu'nicated through aconnecting yoke 21, toa valve stem 20 of a pilot valve 8.

sure in the system exceeding the normal value determined by the weights7, the valve is adapted to admit water or other fluid under pressurefrom an independent pressure supply (not shown), through an inletopening 9, by a port 27 of a safety valve 35, and through a passage 15,to the under side of a fluid-operated motor, the cylinder of which isshown at 13 and the piston at 14. The motor piston 14 will thereupon beraised, the water above the piston exhausting through a passage 16leading from the top of the cylinder 13, and through ports 30 and 50, toan exhaust chamber 22 that communicates, by a cored or drilled passage52 in the side of the valve, with an exhaust opening 10. The movement ofthe motor plston 14 may be communicated, through the piston rod 1 to aflue damper A (Fig. 3) of a steam boiler to effect the closing of thedamper to a greater or lesser degree; or to a rheostat B (Fig. 1) forcontrolling the speed of a pump P or fan V driven by electric motor M;or to a balance-lever valve C '(Fig. 4) for controlling the steampressure or the speed of a fan engine or a turbo blower, or forregulating the speed of a steam-driven pump. These or equivalentcontrolled devices will be hereinafter ineluded within the term damperor the term valve. A partial or total closing of the damper'will shutofi,to a corresponding degree, the air supply to the steam-boilerfurnace, which will result in correspondingly lowering the steampressure. This lowering will continue until the pressure reaches a valuebelow normal, whereupon the valve stem 20 will be moved by the diaphragm2, through the scale beam 5, to its lower efiective position, admittingwater under pressure through the inlet opening 9, and by port 30 andpassage 16, to the upper side of the piston 14. Water will, at the sametime, exhaust by way of the passage 15, leading from the lower side ofthe piston 14, and by the port 27, to the exhaustopening 10. Theconsequent lowering of the piston 14 will be communicated to the damperto efiect an. increase in steam pressure. The structure thus fardescribed is old in the art, the piston 14 oscillating above and below aposition corresponding to normal steam pressure and yielding theabovedescribed hunting efiect.

The preferred mechanism for reducing hunting to a minimum will now bedescribed. Upon .the rod 18, that is secured to the piston rod 17 so asto move therewith, is mounted a vertically disposed wedge or cam member19. The wedge 19 engages a roll 34 at one end of a pivoted bell-cranklever 33, the other end of which is connected ,by a spring 31 to thescale beam5. As themotor piston rises, therefore, in response to themovement of the diaphragm 2, as communicated, through the scale beam 5,to the valve stem 20, the wedge 19 will cause the bell-crank lever 33 toimpose an increasingly greater tension upon the spring 31. This, inturn, will-impart an increasingly greater counteracting force upon thediaphragm 2, preventing sudden or too rapid movement of the valve stem20 to its lower effective position and, therefore, preventing too rapidmovement of the motor piston 14. A similar, but opposite, efieet will beobtained on the downward movement of the piston 14 and of the wedge 19that is movable therewith.

Hunting, is prevented to some extent by the above-described structure,but there would still be a tendency for the valve stem 20, and the motorpiston 14 controlled thereby, to be moved comparatively considerabledistances beyond the positions corresponding to the attainment of normalpressure.

The point of cut olf, at which the pilot valve stem 20 is returned toits neutral position, would, furthermore, be somewhat indefinite,depending upon the friction of the pilot valve. The present invention,however, minimizes such tendency by providing for increasing the tensionin the spring 31, not gradually, but abruptly, or step by step, by

-successive stages of travel that provide definite points of cut off.According to the preferred embodiment of the invention that ishereinillustrated and described, this result is attained by forming aseries of steps 32 upon the wedge 19. Thevalve stem is permitted freeplay to respond to variations in pressure upon the diaphragm 2 so longas the roll 34 engages any particular step,

or is between adjoining stages of travel, but

the roll 34 will engage the next succeeding step if the motor piston 14continues to rise or fall, and this will result'in variation of thecounteracting force applied, through the I spring 31, to the scale beam5. The bellcrank lever 33 and the spring 31 are thus directly controlledby the wedge 19, so as to react upon the scale beam 5 and, through thelatter, upon the valve stem 20 of the stem-pressure device. Thisreaction has the efiect of changing the setting of the ressure device,and, more particularly, 0 the pressure-responsive diaphragm 2, at eachstepped position Further operation of the motor piston 14 is thusprevented at each stepped position, for the valve stem 20 tends thus tobe returned to its neutral position almost immediately upon its beingd1splaced checking the tendency therefrom and simultaneously with thestopping of the motor, the pressure setting is changed a predeterminedamount to balance the change in pressure due to a change in the boilerload. No attempt is made to bring the pressure back to normal. If thepressure returns to normal, it is because the load returns to normal.The operation of the piston 14: of the pressure device is thus effectedin abrupt steps, and hunting action tends to be prevented.

Most fluctuations in steam pressure are of very small magnitude and donot indicate either a permanently rising or a permanently falling load.A large proportion of these negative changes, if permitted to remainundisturbed, would return to normal without regulation. According to thepresent invention, no attempt whatever is made to control such slight ornegative fluctuations. The sudden changing of the pressure setting ofthe pressure-responsive deviceat each of the stepped positions'in theoperation of the motor causes abrupt cutoff at these positions. But itdoes more. It renders the regulator non-responsive at these cut-oftpositions to further variations in pressure until such variations attainfurther, comparatively large, predetermined values. As the regulator ofthe present invention is not responsive to such negative fluctuations,unnecessary changes in furnace conditions is more nearly approached.

If the motor piston is rising, for example, an increased counteractingforce will be applied to the scale beam at the time that the roll 34engages a step 32. This will result in lowering the scale beam so as totend to bring the valve stem 20 back to neutral position. This, in turn,has the immediate effect of partly or wholly shutting off thewater-pressure supply through the inlet opening 9 to the motor and, byso much, of the motor to hunt. Psually, the motor will be broughtcompletely to rest. If the pressure continues to vary in the samedirection, that is, in the example above, to increase, the increasedtension of the spring 31 will soon be overcome and the valve stem willagain be moved in the same direction, that is, raisedf The motor willthen operate again in the same direction until the roll 34 reaches thenext step This process will continue, the motor, at each step, stoppingto await a further variation in pressure before operating again, untilthe stroke of the piston has been completed. Similarly, when thepressure in the system decreases, the scale beam 5, and" the valve stem20 controlled.

thereby, will be lowered, admitting water under pressure above thepiston 14 to force the piston downward. )Vhen the roll 34 reaches a step32 on the downward movewill be brought to rest.

are avoided, and a fixed furnace condition.

ment of the stepped compensating wedge 19, the tension in the spring 31will be somewhat released. The scale beam will thereupon rise to effectthe closing of the valve. The motor cylinder 14 controlled thereby Thisprocess will continue until the do*.*nward stroke of the piston has beencompleted. The motor piston, in accordance with the operation of thediaphragm 2, will thus be brought to rest, or accentuated, at definitesteps in its operation, corresponding closely to the load 011 theboiler; and a further variation in the pressure of the system must takeplace before the motor, and the damper controlled thereby, can beoperated further. Whether the movement of the motor piston is up ordown, the action of the stepped wedge 19 upon the scale beam, throughthe spring 31, is to retard the further movement of the piston. Thehunting tendency is almost entirely eliminated in consequence of theintermittent varying force thus applied to the scale beam, and a degreeof sensitiveness is attained that has not been possible of attainmentheretofore. It has been found, in

practice, that the flow through the valve is regulated in appreciablyexact relation to the demand upon the system, and that theair supply tothe furnace is not varied appreciably more than is absolutely necessaryto compensate for variations in load con ditions.

The stepped stages of travel or compensating points of the motor pistonlamay conveniently be represented upon a graduated scale D. Scales A(Fig. 3), B and C (Fig. 4) may he graduated to indieate correspondingunits of travel of the respectively controlled devices A (Fig. 3), B(Fig. 1) and C (Fig. 4). As the wedge 19 is shown provided with tensteps 32. the. scale D is shown provided with ten divisions. The scalesA (Fig. 3), B (Fig. 1) and C (Fig. 4) are therefore also shown providedwith ten divisions. If the wedge 19 should be provided with a differentnumber of steps, the scales D, A, B and C would be corre- Inn spondinglygraduated. The contact members 36 of the rheostat B are connected to thearmature resistor and the field-magnetwinding resistor that the electricmotors M of pumps for controlling the pressure of the steam-pressuresystem are usually supplied with, and the number of the contact members36 will naturally be the same as the number of wedge steps 32, so thatto each step '32 of the wedge will correspond a definite contact member36. )Vhen the motor piston 14 is brought'to rest, or accentuated, atdefinite steps 32, therefore, the contact arm 37 of the rheostat B willbe con respondingly brought to rest, or accentuated, when in contactwith definite contact mean bers 36.

j Maximum draft or air supply should be supplied at the load peak, butnot before the peak is reached. A negative change in pressure with afluctuating boiler load is equivalent to a positive change with auniform load. The pressure-operating range, that is, theamount that thesteam pressure may vary between minimum and maximum air supply to theboiler furnace, or the amount that it varies between minimum and maximumlimits of travel of the regulator, must accordingly be wide enough toinclude the possible variations in load in order that the air supply maybe consistent with the boiler load, and an excessive deficiency of theair supply may be avoided. Adjustable .means are therefore provided foreffecting a varying pressure-operating range between minimum and maximumair supply to the boiler furnace. In the specific embodiment of theinvention that is herein illustrated and described, this result isattained by adjusting the angle or taper of the wedge 19. To this end,the wedge is pivoted at one end 56 and the other end 58 is adjustablyengaged by a set screw 60 that may be locked in any desired position inany well-known manner, as by a check nut 62. By adjusting the screw 60,furthermore, it is possible to vary the pressure operating range betweenminimum and maximum demands to meet various conditions of service.

A change in pressure setting is thus effected that is equivalent to thateffected at the stepped position plus that effected between steppedpositions.

In further illustration of the principles underlying the presentinvention, let it be assumed, for concreteness, that the regulator isprovided with ten non-responsive regulating points. The motor plungerwill, there fore, occupy the mid position of its stroke at the fifthstep. At this time, the regulator should be balanced to the mean averagepressure or boiler load. This may readily be arranged by manuallyadjusting the scale beam 5 by means of the counter weights 7.

Let it further be assumed, for definiteness, that the mean averagepressure is 100 pounds, and that the operating range is five poundsabove and below this average pressure. At a pressure of 101. pounds,therefore, the roll 34 is on the sixth ste The motor is caused tooperate to adjust t e pressure device to balance the load at 101 pounds.The motor does this adjusting automatically. A similar process takesplace when the pressure is at 102 pounds, 103 pounds, and so on, up to105 pounds, at which point there is no load to require air. At alltimes. the air is supplied in accordance with the load. and not inexcess of the load. The boiler load or pressure is thus maintained orbalanced at each predetermined value of the boiler load or pressureabove or below the mean average setting. lVithin very narrow limits, thedraft does not vary from this value.

A similar effect is obtained with a receding load. \Vhen the pressuredrops to 99 pounds, the roll 34 is on the fourth step.

The pressure thus tends to be maintained at 99 pounds, and there will beno further drop in pressure unless there is a further increase in theload.

At these definite cut-off points, the boiler load is balanced by the airsupply and hunting action is, by so much, eliminated.

Modifications may be made by persons skilled in the art withoutdeparting from the spirit of the invention, and such modifications areintended to be included within the scope of the invention, as defined inthe appended claims.

\Vhat is claimed as new is:

1. In a pressure-regulator system, the combination with a fluid system,means for controlling the pressure obtaining in said system, and apressure device operated in accordance with the pressure obtaining inthe fluid system, of a cam member operated by said device foraccentuating the positions of said controlling means.

2. In a pressure-regulator system, the combination with amotor-controlling means, and a fluid-pressure-operated device, of a cammember operated by said pressure device for accentuating the positionsof said motor-controlling means, and means associated with said cammember for so reacting on said pressure device as to change its setting.

3. In a pressure-regulator system, the combination with amotor-controlling rheostat, and a fluid-pressure device, of a cam memberfor effecting operation of said rheostat in definite steps in accordancewith the operation of said pressure device, and means directlycontrolled by said cam member for so reacting on said pressure device asto change its setting.

4. I11 :1 pressure-regulator system, the combination with a.fluid-pressure system, a motor-controlling mechanism, and a pressuredevice 0 erated in accordance with the pressure obtaining in said fluidsystem, of a cam member operated by said device for accentuating thepositions of said motor-controlling mechanism and for effecting theoperation of said device in abrupt steps.

5. In a pressure-regulator system, the combination with a fluid system,means comprising a motor-controlling device for governing the pressureobtaining in said fluid system, and a pressure device operated inaccordance with the pressure obtaining in said fluid system foroperating said device, of a cam member operated by said device foraccentuating the positions of said 1notor-controlling device, and meansactuated by said cam member for reacting on said pressure device toprevent hunting action.

6. In a pressure-regulator system, the combination with a fluid system,a pump for controlling the pressure in said fluid system, a motor foroperatin said pump, and a rheostat having resistors in circuit with thearmature and the field-magnet winding of the motor, of means comprisinga pressure device for operating said rheostat in accordance with thepressure obtaining in the fluid system, said means including a cammember operated by said device for accentuating the positions of saidrheostat and for opposing further operation of the pressure device.

7. In a pressure-regulator system, the combination with a fluid system,a rheostat, and a fluid-pressure device operated in accordance with thepressure obtaining in said [luid system for operating said rheostat, ofmeans comprising a cam member operated by said device for accentuatingthe positions of said rheostat.

8. In a combination with a fluid-pressure system, a pump for controllingthe pressure in said system, a motor for operating said pump, and arheostat havingresistors in the circuit of the armature and thefield-magnet winding of said motor, of a pressure device operated inaccordance with the pressure obtaining in said fluid system foroperating said rheostat, and a cam.member for accentuating the positionsof said rheostat and for reacting on said device to change its setting.

9. In a pressure system, a motor for controlling the pressure in thesystem, a valve for controlling the motor, a diaphragm controlled inaccordance with the said pressure :t'or operating the valve, andcompensating means controlled by the motor for counteracting step bystep the action of the diaphragm with abruptly increasing and decreasingcounter action at the said steps, whereby the valve checks the furtheroperation of the motor at the said steps.

10. In a pressure system, a motor for controlling the pressure in thesystem, means controlledin accordance with said pressure for controllingthe motor, and a stepped compensating wedge movable by the motor forcounteracting step by step the action of the controlling means withabruptly increasing and decreasing counteraction at the steps'ot thewedge, whereby the further operation of the motor becomes checked at thesaid steps.

l1. lln a pressure system, means for controlling the pressure in thesystem, means controlled in accordance with said pressure forcontrolling the pressure-controlling means, compensating means forcounteracting step by step the action of the secondpressure-regulatorsystem, the

v named means with abruptly increasing and decreasing counter action atthe said steps, whereby the first-named means becomes checked at thesaid steps, and means for adjusting the compensating means.

12. In a pressure system, a motor for controlling the pressure'inthesystem, a Valve for controlling the motor, a diaphragm controlled inaccordance with said pressure for operating the valve, means forcounteracting the action of the diaphragm, and means whereby the actionof the counteracting means is abruptlyv increased and decreased step bystep in successive stepped positions of the motor, whereby the valvechecks the "further operation of the motor at the said steps. V m

18. The combination with a fluid-pressure motor having a movable member,of a pressure device and a controlling valve for operating the movable mmber of said motor, said motor having an adjustable wedge connected withits movable member, the adjustable wedge having steps, and an armarranged to be engagd by the steps of the wedge for effecting a stopping(it said motor at each stepped position on said Wedge.

14.. In a pressure system. a motor for corn trolling the pressure in thesystem, a valve for controlling the motor, a scale beanaconnocted to thevalve, a diaphragm controlled Oil tilt

in accordance with said pressure and connected to the scale beam forefi'ecting the operation of the valve, a stepped compensating wedgepivoted at one end to the motor, a bell-crank lever one arm of which isen--.v gaged by the steps of the wedge, a spring for counteracting theforce exerted by the diaphragm connected at one end to the other arm ofthe bell-crank lever and at the other end to the scale beam, and meansoperable at the other end of the wedge for adjusting the wedge.

, 15. In a pressure system, means for controlling the pressure in thesystem, means controlled in accordance with saidpressure for controllingthe pressurecontrolling means, compensating means for counteracting stepby step the action of the second named means with abruptly increasingand decreasing counter action at the said steps, wherebv the controllingmeans becomes checked at the said steps, and a sca e graduated in unitscorresponding to the said steps of action of the compensating-means forindicating the action of the compensating means.

16. In a pressure system, a motor for controlling the pressure in thesystem. a valve having a neutral position in which it is in effectiveand anefiective position in which it controls the operation ofthe-motor. a scale beam connected to the valve. a diaphragm controlledin accordance with the said pressure and connected to the scale beam foreffecting the operation of the valve to the efiective position, vandmeans for returning the valve to the neutral position,

' pressure in the system for operating the valve to the effectiveposition, and means for returning the valve to the neutral position,there being a spring connection between the valve-returning means andthe valve-operating means.

18. In a pressure system, a motor for controlling the pressure in thesystem, a valve for controlling the motor, means controlled inaccordance with the said pressure for controlling the valve, and astepped compensating wedge controlled by the motor and connected to thevalve-controlling means for counteracting step by step the action of thecontrolling means with abruptly increasing and decreasing counter actionat the steps of the wedge, whereby thevalve checks the further operationof the motor at the said steps.

' 19. In a pressure system, means for controlling the pressure in thesystem, means controlled in accordance with the said pressure forcontrolling the pressure-controlling means, a stepped compensating wedgefor i counteracting step by step the actionof the second-named meanswith abruptly increasing and decreasing counter action at the saidsteps, whereby the operation of the firsttill named means becomeschecked at the said steps, and means for adjusting the angle of thewedge. l

20. In a pressure system, a motor for controlling the pressure inthesystem, a controlling element having a neutral position in which itis inefiective and two efiective positions in which it controls theoperation of the motor and its direction of operation, apressure-responsive device responsive to variations in pressure in thesystem, means connecting the pressure-responsive device to thecontrolling element to actuate the element to, the effective positions,stepped compensating means operated by the motor to efl'ect an abruptoperation oi": thecontrolling element to its neutral position at aplurality of fixed predetermined points between the limits of operationof the motor, there being a spring connection between the first-namedmeans and the compensating means for efiecting a change in pressuresetting of the pressure-responsive device, and means to adjust thecompensating means to vary the range of pressure setting between thelimits of operation of the motor.

21. In a pressure regulator, a motor, two elements having a relativeneutral position in which they are ineffective and a relative efiectiveposition in which they control the ting, and means for changing thepressure setting of the device at fixed, predetermined points in theoperation of the motor by predetermined pressure values above and belowthe average pressure setting and to cause the device to relativelyactuate the elements at the said predetermined pressure values, and forrelatively returning the elements to the relative neutral position atthe said fixed, predetermined points in-the'operation of the motor.

22. In a pressure system, a motor for con trolling the pressure in thesystem, a valve having a neutral position in which it is inefiective andan effective position in which it controls the operation of the motor,means controlled in accordance with the pressure in the system foroperating the valve to the effective position, a compensating steppedwedge connected to the motor so as to move therewith, and meansconnecting the steps of the wedge with the valve to effect the return ofthe valve to the neutral position.

23. In a pressure system, a motor for controlling the pressure in thesystem, means controlled in accordance with the said pressure forcontrolling the motor, compensating means for counteracting step by stepthe action of the controlling means with abruptly increasing anddecreasing counter action at the said steps, whereby the furtheroperation of the motor becomes checked at the said steps, and meanswhereby the operation of the motor is unchecked between the said steps.a

24. In a pressure system, means for con A i trolling the pressure in thesystem, means controlled in accordance with the said pressure forcontrolling the pressure-controlling means, a compensating wedge forcounteracting the action of the second-named means, and means foradjusting the wedge.

25. ltn a fluid system, a fluid motor for controlling the condition ofthe fluid in the system, a source of fluid for the motor independent ofthe fluid in the system, and a cam for accentuating the operation of themotor.

26. ltn combination, a pressure device. two elements having a relativeneutral position in which they are ineffective and a relative efiectiveposition in which they control the tively actuating the elements to therelative effective position, and a stepped cam ior nee-aces relativelyreturning the elements to the relative neutral position.

27. In combination, a motor, two elements having a relative neutralposition in which they are ineffective and a relative effective positionin which they control the operation of the motor, means for relativelyactuating the elements to the relative effective position, and a steppedcam controlled by the motor for relatively returning the elements to therelative neutral position, whereby the motor is operated in abrupt stepscorresponding to the steps of the cam.

28. In combination, a rheostat, a motor for controlling the positions ofthe rheostat, two elements having a relative neutral position in whichthey are ineffective and a relative effective position in which theycontrol the operation of the motor, means for relatively actuating theelements to the relative effective position, and a stepped cam forrelatively returning the elements to the relative neutral position.

29. In a fluid system, means for controlling the condition of the fluidin the system, two elements having a relative neutral position in whichthey are ineffective and a relative efiective position in which they control the operation of the controlling means, means controlled inaccordance with the condition of the fluid in the system for rela tivelyactuating the elements to the relative effective position, and a steppedcam for relatively returning the elements to the relative neutralposition.

30. In combination, a pressure device, a motor operable step by step forcontrolling the pressure upon the pressure device, two elements having arelative neutral position in which they are ineffective and two relative effective positions in which they control the operat on of' themotor in opposite directions, means controlled by the pressure devicefor relatively actuating the elements to the relative effectivepositions, and a stepped cam for relatively returning the elements tothe relative neutral position at stepped positions in the operation ofthe motor.

31. In a fluid system, a motor for controlling the condition of thefluid in the system, a valve for controlling the motor, means controlledin accordance with the condition of the fluid in the system for openingthe valve, and a stepped cam controlled by the motor for closing thevalve.

32. The combination with a motor and a pressure device, of a controllingvalve for said motor having a neutral position and two effectivepositions, a graduated step compensator associated with said motor, and

means for adjusting said compensator to' effect the stopping of themotor at each compensating point. 1

"a; In combination, a motor, a controlling valve for the motor arrangednormally to occupy a neutral position and having two effectivepositions, a pressure device for ac tuatingsaid valve to one or theother of said effective positions, and a graduated step compensatorconnected with said motor and arranged to apply a varying counteractingforce to'said pressure device for returning said valve to its neutralposition at each compensating point of the motor travel.

34. In a fluid system, means operable step by step for controlling thecondition" of the fluid in the system, a cam controlled in accordancewith the condition of the fluid in the system for accentuating the stepsof operation of the controlling means, and means for varying from stepto step the operative effect of the cam. v

In a fluid system, means for controlling the condition of the fluid inthe system, two elements having a relative neutral position in whichthey are ineffective and a relative effective position in which theycontrol the operation of the controlling means, means controlled inaccordance with the condition of the fiuid in the system for relative--ly actuating the elements to the relative effective position, andcompensating means for counteracting step by step the action of theactuating means to return the elements to the relative'neutral positionwith abruptly increasing and decreasing counteraction at the said steps,whereby the controlling means is operated in abrupt steps correspondingto the said steps of the compensating means.

36. In a fluid system, a motor operable step by step for controlling thecondition of the fluid in the system, two elements having a relativeneutral position in which they are ineffective and two relativeeffective posi tions in which they control the operation of the motor inopposite directions, a pressure device controlled in accordance with thecondition of the fluid in the system for relatively actuating theelements to the relative eff-cct-ive positions, a step compensatorcontrolled by the motor for relatively returning. the elements to therelative neutral position at stepped positions in the operation of themotor, and means for varying from step to step the pressure setting ofthe pressure device at which the elements are relatively actuated to therelative effective positions by the pressure device.

37. The combination with a fluid-pressure motor. of a pressure deviceand a controlling valve'for operating said motor. a stepped wedgeoperated by said motor, means for adjusting the angularity of saidwedge, an arm, said steps being arranged to engage the arm for effectinga stopping of said motor at each of the stepped positions on said wedge,and means for changing the pressure setting of the pressure device ateach stopping point of the fluid-pressure motor.

38. In a fluid system, a motor for controllift ling the condition of thefluid in the system, two elements having a relative neutral posi tion inwhichthey are ineffectivev and two relative effective positions in whichthey control the operation of the motor, means controlled in accordancewith the condition of the fluid in the system for relatively actuatingthe elements to the relative effective positions, and means controlledby the motor for relatively returning the elements to the relativeneutral position, there being an elastic connection between thereturning means and the actuating means.

39. In combination, a rheostat, two elevalve at predetermined points inthe operation of the motor.

44. In combination, a pressure device, a motor for controlling thepressure upon the pressure device, two elements having a relativeneutral position in which they are ineffective and two relativeeffective positions in which they control the operation of the motor inopposite directions, means controlled by the pressure device forrelatively actuating the elements to the relative e fective positions,and means for relatively returning the elements to the relative neutralposition at predetermined points in the ments having a relative neutralposition in ,roperation of the motor.

which they are ineffective and a relative effective position in whichthey control the operation of the rheostat, means for relativelyactuating the elements to the relative effective position, and means forrelatively returning the elements to the relative neutral position atpredetermined points in the operation of the rheostat.

40. In avfluid system, a motor for controlling the condition of thefluid in the system, two elements having a relative neutral position inwhich they are ineffective and a relative effective posit-ion in whichthey control the operation of the motor, means controlled in accordancewith the condition of the fluid in the system for relatively actuatingthe elements to the relative effective position, and means forrelatively returning the elements to the relative neutral position atpredetermined points in the operation of the motor.

41. In combination, a pressure device, a motor for controlling thepressure upon the pressure device, two elements having a relativeneutral position in which they are ineffective and a relative effectiveposition in which they control the operation of the motor, a membercontrolled by the pressure device, means actuated by the member'toeffect the relative actuation of the elements to the relative effectiveposition, and means for relatively returning the elements to therelative neutral position at predetermined points in the operation ofthe motor.

42. The combination with a fluid-pressure motor, of a pressure deviceand a controlling valve for operating the motor, an operating member forsaid valve, means connecting said valve and said operating member, and

, means for shifting the controlling valve from a pressure to a cut-offposition at predetermined points in the movement of the fluid-pressuremotor.

43. In a fluid system, a motor for controlling the condition of thefluid in thesystem, a valve for controlling the motor, means controlledin accordance with the condition of the fluid in the system for openingthe valve, and means for closing the 45. The combination with afluid-pressure motor, of a pressure device and a controlling valve foroperating the motor, an operating member of said valve, means connectingsaid valve and said operating member, means for shifting the controllingvalve from a pressure to a cut-off position at predetermined points inthe movement of the fluidpressure motor, and means for adjusting thesecond-named means to eflect a greater or a less pressure variationacting on the pres sure device for a .given movement of thefluid-pressure motor.

4:6. The combination with a fluid-pressure motor, of a pressure deviceand a controlling valve for operating the motor, a hinged Wedge operatedby said motor, means for adjusting the angularity of said wedge, an armheld in contact with the adjustable wedge, and means operated by saidarm for effecting a stopping of said motor.

47. In a fluid system, a motor for controlling the condition of thefluid in the system, two elements having a relative neutral position inwhich they are ineffective and a relative eflective position in whichthey control the operation of the motor, means responsive to variationsin the condition of the fluid in the system for relatively actuating theelements to the relative eflective position, means controlled by themotor for relatively returning the elements to the relative neutralposition at predetermined points in the operation of the motor, andmeans for rendering the regulator non-responsive to predeterminedchanges in the condition of the fluid in the system at each of the saidpredetermined positions.

48.-In a fluid system, a motor for controlling the condition of thefluid in the system, two elements having a relative neutral position inwhich they are ineffective and a relative eflective position in whichthey control the operation of the motor,

means responsive to variations in the condition of the fluid in thesystem for relatively actuating the elements to the relative eflectiveposition, and means for abruptly returning the elements to the relativeneutral reeaeee position at predetermined points in the operation of themotor to abruptly stop the motor at the predetermined points, the motorbeing adapted to operate freely hetween the predetermined points.

49. In a fluid system, a motor for controlling the condition of thefluid in the system, two elements having a relative neutral position inwhich they are inefl'ective and a relative effective position in whichthey control the operation of the motor, a pressure-responsive devicecontrolled in accordance with the condition of the fluid in the systemfor relatively actuating the elements to the relative efi'ectiveposition, means for relatively returning the elements to the relativeneutral position at prede tel-mined points in the operation of the motorand to interrupt the operation of the motor at the said predeterminedpoints, and means for changing the pressuresetting of thepressure-responsive device simultaneously with the interruption of themotor operation.

, 50. In a pressure system, a motor for controlling the pressure in thesystem, two elements having a relative neutral position in which theyare ineffective and a relative effective position in which they controlthe operation of the motor, a device responsive to variations in thepressure of the system for relatively actuating the elements to the.relative efiective position, means controlled by the motor forrelatively returning the elements to the relative neutral position atpredetermined points in the operation of the motor, and means forrendering the said device ineflective to relatively actuate the elementsin response to predetermined changes in the pressure of the system ateach of the said predetermined positions.

51. In a fluid system, means for controlling the condition of the fluidin the system, a motor for controlling the controlling means, adevice-responsive to variations in the condition of the fluid in thesystem for controlling the operation of the motor, and means forstopping the motor at the end of predetermined steps of operation of themotor of predetermined len th and for changingthe pressure setting 0 thedevice at the ends of the said predetermined steps.

52. In a fluid system, means for controlling the condition of the fluidin the system, a motor for controlling the controlling means, a deviceresponsive to variations in the condition of the fluid in the system forcontrolling the operation of the motor, and means for stopping the motorat predetermined points in the operation of the motor and for changingthe setting at which the device operates at the predetermined points.

In testimony whereof, I have hereunto subscribed my name this 19th dayof October, 1923.

are LEWIS KIMBALL.

